Scroll Fluid Machine

ABSTRACT

A scroll fluid machine having a scroll unit that includes a fixed scroll ( 36 ) and a movable scroll ( 38 ) that are each constructed from an end plate and a scroll wall integral with the end plate, and also includes a chip seal ( 42 ) provided at the tip of the scroll wall of one of the scrolls and in relative sliding contact with the end plate of the other scroll. For example, a part (radial projection) of a chip seal ( 42 ) on the movable scroll side is projected from an outer wall surface of a scroll wall ( 38   b ), and when a pressure chamber is formed between the fixed scroll and the movable scroll, the radial projection is in relative sliding contact with the inner wall surface of a scroll wall ( 36   b ) of the fixed scroll to secure a fine gap (G) between the inner and outer wall surfaces. The simple structure as above can relax conditions of sliding between the scroll walls with sealability of the pressure chamber maintained, and the scroll fluid machine has excellent durability.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a scroll fluid machine, and specifically, to a scroll fluid machine improved in durability of scroll unit.

BACKGROUND ART OF THE INVENTION

For example, a scroll fluid machine used as a fluid machine in a refrigeration circuit of an air conditioning system for vehicles has a scroll unit, and the scroll unit includes a fixed scroll and a movable scroll. Each of these fixed scroll and movable scroll has an end plate and a scroll wall integral with the end plate, and the scrolls are disposed at a condition where both scroll walls are engaged with each other so that therebetween a gas-tight pressure chamber (fluid pocket) is formed via a chip seal on the tip of the scroll wall. The movable scroll is operated at an orbital movement relative to the fixed scroll by receiving a drive force via an orbital unit, and by the change of the displacement and the position of the above-described pressure chamber accompanied with this orbital movement, the fluid (fro example, refrigerant) in the pressure chamber is compressed or expanded (for example, Patent document 1).

Patent document 1: JP-A-8-261171

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In the conventional scroll fluid machine as described above, because the scroll walls of the fixed scroll and the movable scroll locally slide relatively to each other to form a pressure chamber, if the sliding contact condition between the scroll walls can be relaxed, the lives of these fixed scroll and movable scroll, ultimately, the life of the fluid machine, may be extended.

Where, in order to relax the sliding contact condition between the scroll walls, for example, a fine gap may be secured between both scroll walls within a range which does not decrease the sealability of the pressure chamber, and the scroll walls may be in non-sliding contact with each other. In order to secure a fine gap, however, the processing accuracy and the assembly accuracy of not only the fixed scroll and the movable scroll but also the orbital unit have to be increased.

Further, because a great centrifugal force acts on the movable scroll as its orbital speed becomes faster, if a fine gap is secured, the orbital posture of the movable scroll in a high speed range becomes unstable, and depending upon the posture, there may be a fear that a galling occurs between the scroll walls. Therefore, when a fine gap is secured, it is necessary to increase the rigidity of the orbital unit or to employ a design change such as addition of parts to the orbital unit, so as to stabilize the orbital posture of the movable scroll.

Thus, if a fine gap is tried to be provided between the scroll walls, it becomes necessary to increase the processing accuracy or the assembly accuracy of the scroll unit or the orbital unit, to increase the rigidity of the orbital unit, or to change the design such as addition of parts to the orbital unit, and therefore, reduction in productivity or cost up of the fluid machine may be caused.

Accordingly, an object of the present invention is to provide a scroll fluid machine which can relax the sliding contact condition between scroll walls by a simple structure while maintaining a good sealability of a pressure chamber, thereby having an excellent durability.

Means for Solving the Problems

To achieve the above object, a scroll fluid machine according to the present invention has a scroll unit that comprises a fixed scroll and a movable scroll each constructed from an end plate and a scroll wall integral with the end plate, and comprises a chip seal provided at a tip of a scroll wall of one of the scrolls and in relative sliding contact with an end plate of the other scroll, and is characterized in that the scroll unit further comprises a radial projection provided on a first wall surface as one of wall surfaces of the scroll walls facing each other and being in relative sliding contact with a second wall surface as the other wall surface to secure a fine gap between the wall surfaces when a pressure chamber (fluid pocket) is formed between the fixed scroll and the movable scroll.

In such a scroll fluid machine according to the present invention, although the above-described radial projection may be formed separately from the chip seal, it is preferred that the radial projection is formed integrally with the chip seal. In this case, it is preferred that the chip seal includes a top seal surface which is in relative sliding contact with the end plate of the other scroll, and a sliding contact surface which is connected perpendicularly to a side edge of the top seal surface and which is positioned relatively to the first wall surface with a distance corresponding to the fine gap.

Further, the above-described scroll unit may further comprise a holding means for holding the chip seal at the tip of the scroll wall. This holding means may comprise a recessed portion and a projected portion which are provided on the chip seal and the scroll wall and which are engaged with each other. Furthermore, as a preferable embodiment, the holding means may comprise an adhesive layer.

Further, although the material for the chip seal is not particularly limited, preferably it is made of one material selected from the group consisting of a polyphenylenesulfide group resin, a polyetheretherketone group resin and a polyimide group resin.

Various forms can be employed as the scroll fluid machine according to the present invention, and for example, it can be formed as a compressor or an expander, and further, as a scroll fluid machine having both functions of compression and expansion. For example, it can be structured as a scroll fluid machine wherein a motor is further provided, and the scroll unit is provided on each end of a rotational shaft of the motor.

Effect According to the Invention

In the scroll fluid machine according to the present invention, since the radial projection secures a fine gap between the wall surfaces of both scroll walls, the sliding contact condition between the scroll walls can be relaxed while the sealability of the pressure chamber can be maintained, and abrasion of the scroll walls can be suppressed. Further, in this fluid machine, by the structure in which the radial projection secures a fine gap between the wall surfaces of the scroll walls, even if the movable scroll is operated at a high-speed orbital movement, the orbital posture of the movable scroll is not disturbed, and occurrence of a galling between the scroll walls can be prevented. Consequently, the fluid machine according to the present invention has an excellent durability.

Further, in the scroll fluid machine according to the present invention, by the structure in which a fine gap is secured between the scroll walls, it is not necessary to mix a lubricant oil in the operational fluid, and the structure is preferable for making the machine oil-free. Therefore, for example, in a refrigeration circuit applied with this fluid machine, because it is not necessary to mix a lubricant oil in the refrigerant, the coefficient of performance of the refrigeration circuit is improved. Moreover, because it is not necessary to mix a lubricant oil in the operational fluid, this fluid machine can be applied to various uses.

Further, in the scroll fluid machine according to the present invention, if the radial projection is formed integrally with the chip seal, because the number of parts does not increase, reduction in productivity and cost up can be prevented. Further, by the structure in which the radial projection is formed integrally with the chip seal, because a fine gap can be easily secured even at a position which is most apart from an end portion of a drive shaft supporting the movable scroll, even when the movable scroll is operated at a high-speed orbital movement, disturbance of the orbital posture of the movable scroll can be surely prevented.

Further, in a case where the chip seal has a top seal surface and a sliding contact surface for securing a fine gap, while an excellent durability can be given to each of the top seal surface and the sliding contact surface, both surfaces can well exhibit respective target functions. Further, in this case, because the chip seal has the top seal surface projecting from the tip of the scroll wall, during the operation, the surface contact pressure between the chip seal and the end plate may be reduced appropriately, and the durability of the chip seal may be increased.

Further, in a case where a holding means for holding the chip seal at the tip of the scroll wall is further provided, it becomes possible to easily hold the radial projection on the scroll wall side by this holding means. Further, by the structure in which the holding means includes a recessed portion and a projected portion which are provided on the chip seal and the scroll wall and which are engaged with each other, the radial projection can be held on the scroll wall side more easily and more securely. Furthermore, by the structure in which the holding means includes an adhesive layer, the radial projection can be held on the scroll wall side further easily and further securely.

Further, in a case where the chip seal is made of one material selected from the group consisting of a polyphenylenesulfide group resin (PPS group resin), a polyetheretherketone group resin (PEEK group resin) and a polyimide group resin (PI group resin) which are excellent in abrasion resistance, the durability of the scroll fluid machine can be further increased.

Furthermore, in a case where the scroll fluid machine according to the present invention is formed as a structure wherein a motor is further provided, and the scroll unit is provided on each end of a rotational shaft of this motor (namely, a structure having two pressure chambers), it is possible to use one pressure chamber as a chamber for compression and use the other pressure chamber as a chamber for expansion. In such a structure, since the expansion energy of an operational fluid in the expansion chamber can be used as an auxiliary power for compressing an operational fluid in the compression chamber, the consumption power may be saved.

BRIEF EXPLANATION OF DRAWINGS

FIG. 1 is a vertical sectional view of a scroll fluid machine applied to a refrigeration circuit according to an embodiment of the present invention.

FIG. 2 is a back surface view of a chip seal applied to the fluid machine depicted in FIG. 1.

FIG. 3 is an elevational view of a movable scroll applied to the fluid machine depicted in FIG. 1.

FIG. 4 is a plan view showing the movable scroll depicted in FIG. 3 together with the chip seal depicted in FIG. 2.

FIG. 5 is an enlarged, partial sectional view as viewed along V-V line of FIG. 4.

FIG. 6 is an explanation diagram showing the sliding contact position between scroll walls of a fixed scroll and a movable scroll and a chip seal in the fluid machine depicted in FIG. 1.

FIG. 7 is an elevational view of a movable scroll according to a modification of the present invention.

FIG. 8 is a sectional view showing a part of a scroll wall together with a chip seal according to a modification of the present invention.

FIG. 9 is a sectional view showing a part of a scroll wall together with a chip seal and a radial projection according to another modification of the present invention.

EXPLANATION OF SYMBOLS

-   1: scroll fluid machine -   35: scroll unit -   36: fixed scroll -   38: movable scroll -   36 a, 38 a: end plate -   36 b, 38 b: scroll wall -   40: pressure chamber -   42: chip seal -   42 b: seal surface (top seal surface) -   42 c: outer side surface (sliding contact surface) -   G: fine gap

THE BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments of the present invention will be explained referring to figures.

FIG. 1 depicts a scroll fluid machine 1 according to an embodiment of the present invention, which is applied, for example, to a refrigeration circuit of an air conditioning system for vehicles. The refrigeration circuit has a circulation passageway 2, and refrigerant as the operational fluid is circulated in the circulation passageway 2. Where, a lubricant oil is not mixed in the refrigerant, and this refrigeration circuit is oil free. In this embodiment, fluid machine 1 has both functions of a compressor and an expander, and the fluid machine disposed in circulation passageway 2 divides the circulation passageway 2 into a high-pressure region 2 a and a low-pressure region 2 b. In high-pressure region 2 a, a condenser 4 and a receiver 6 are disposed in order in the circulation direction of refrigerant, and in low-pressure region 2 b, an evaporator 8 is interposed.

Fluid machine 1 has a motor housing 10, and the motor housing 10 has a motor casing 12 with a cup-like shape and an end plate 14 fixed to the opening end of the motor casing 12. A cylindrical stator 16 is fitted into a circumferential wall 12 a of casing 12, and stator 16 surrounds a columnar rotor 18 free to rotate. A drive shaft 20 extends through the center of rotor 18, and the rotor 18 rotates integrally with drive shaft 20. Shaft holes are provided on the central parts of end wall 12 b of casing 12 and end plate 14, respectively, and both end portions of drive shaft 20 are projected from these shaft holes. Drive shaft 20 is supported free to rotate by end wall 12 b and end plate 14 via ball bearings 22 provided in the shaft holes. Further, in the shaft holes, lip seals 24 are provided at positions outside ball bearings 22, and the shaft holes are closed by the lip seals 24.

A power supply port 26 is provided to circumferential wall 12 a of motor casing 12, and power can be supplied to stator 16 from an external power source (not shown) through power supply port 26. When power is supplied to stator 16, rotor is rotated by the electromagnetic force of stator 16, thereby rotating drive shaft 20.

A compression housing is provided to each end of the above-described motor housing 10, and the compression housing has a cup-like compression casing 30. Compression casing 30 is fixed to motor housing 10 by a plurality of bolts 32, and the opening end of compression casing 30 is fitted at a gas-tight condition to each end of motor housing 10 via O-ring 34.

A scroll unit 35 is provided in compression casing 30, and scroll unit 35 has metal fixed scroll 36 and movable scroll 38. These fixed scroll 36 and movable scroll 38 have end plates 36 a, 38 a and scroll walls 36 b, 38 b integral with end plates 36 a, 38 a, and in this fluid machine 1, the end wall of compression casing 30 is formed also as end plate 36 a of fixed scroll 36.

These fixed scroll 36 and movable scroll 38 are disposed so as to be engaged with each other in order to form pressure chamber 40 (fluid pocket) therebetween. Under this disposition, movable scroll 38 can be operated at an orbital movement relative to fixed scroll 36, and accompanied with this orbital movement, pressure chamber 40 is changed in its displacement as well as in its position.

Resin chip seals 42 are provided on the tips of scroll walls 36 b, 38 b, respectively, and scroll walls 36 b, 38 b of fixed scroll 36 and movable scroll 38 are in sliding contact with end plates 36 a, 38 a of scrolls 36, 38 positioned at the respective counter sides, via chip seals 42.

Hereinafter, chip seal 42 will be explained, and because the structures of chip seals 42 provided on fixed scroll 36 and movable scroll 38, and fixing means of chip seals 42 to scroll walls 36 b, 38 b, are same as each other, the explanation will be carried out by exemplifying chip seal 42 of movable scroll 38 side.

As shown in FIG. 2, chip seal 42 extends spirally, and has constant width and thickness. From the back surface among both flat surfaces parallel to each other which define the thickness of chip seal 42, pins 42 a are projected at predetermined positions in the lengthwise direction (spiral direction).

As shown in FIG. 3, on the tip of scroll wall 38 b to be attached with chip seal 42, the region connected to the outer wall surface among both wall surfaces of scroll wall 38 b is formed as a flat surface 46 at a position close to end plate 38 a as compared with tip surface 44 connected to the inner wall surface. Flat surface 46 also extends spirally, and pin holes 46 a are formed at predetermined positions in the lengthwise direction.

As shown in FIG. 4, chip seal 42 is overlapped with flat surface 46, and at that time, pins 42 a are inserted into pin holes 46 a. Therefore, as shown in FIG. 4, by the fitting of pins 42 a into pin holes 46 a, chip seal 42 is fixed to the tip of scroll wall 38 b.

Where, as shown in FIG. 5, a part of chip seal 42 is projected at a predetermined length from tip surface 44 of scroll wall 38 b in the thickness direction of chip seal 42, and the front surface of chip seal 42 is parallel to the tip surface 44 of scroll wall 38 b, but is positioned near end plate 36 a of fixed scroll 36 as compared with the tip surface 44. Therefore, the front surface of chip seal 42 forms a seal surface 42 b which is in sliding contact with end plate 36 a of fixed scroll 36, over its entire region.

Further, a part of chip seal 42 is projected at a predetermined length from the outer wall surface of scroll wall 38 b in the width direction of chip seal 42 (the radial direction of scroll wall 38 b), and outer side surface 42 c among both side surfaces defining the width of chip seal 42 is parallel to the outer wall surface of scroll wall 38 b, but is positioned near the inner wall surface of scroll wall 36 b of fixed scroll 36 as compared with this outer wall surface. Therefore, at the position in the lengthwise direction where scroll walls 36 b, 38 b are closest to each other, outer side surface 42 c of chip seal 42 is in sliding contact with the inner wall surface of scroll wall 36 b of fixed scroll 36. At this position in the lengthwise direction, a fine gap G is formed between the inner and outer wall surfaces of scroll walls 36 b, 38 b via chip seal 42.

In more detail, FIG. 6 is a modification diagram for explaining the sliding contact positions between scroll walls 36 b, 38 b and outer side surface 42 c of chip seal 42, and outer side surface 42 c of chip seal 42 at movable scroll 38 side is in sliding contact with the inner wall surface of scroll wall 36 b of fixed scroll 36 at two positions (points A, B). On the other hand, outer side surface 42 c of chip seal 42 at fixed scroll 36 side is in sliding contact with the inner wall surface of scroll wall 38 b of movable scroll 38 at two positions (points C, D).

Fine gap G is formed between the inner and outer wall surfaces of scroll walls 36 b, 38 b at each of these points A, B, C, D in the lengthwise direction, and each of points A, B, C, D is positioned at each end of each pressure chamber 40 in the lengthwise direction of scroll walls 36 b, 38 b. Where, outer side surface 42 c of each chip seal 42 is in sliding contact with the inner wall surface at a position near the root of each of scroll walls 36 b, 38 b. Further, in FIGS. 4 and 6, in order to indicate chip seal 42 clearly, the hatching is provided only to chip seal 42.

Referring to FIG. 1 again, movable scroll 38 is connected to each end of drive shaft 20 via an orbital unit to enable the orbital movement of movable scroll 38. In more detail, an eccentric bush 50 is fixed to each end of drive shaft 20, and the eccentric bush 50 can be rotated integrally with drive shaft 20. Eccentric bush 50 is surrounded by a boss provided integrally to the outer surface of end plate 38 a, and between the eccentric bush 50 and the boss, ball bearing 52 is interposed.

Further, a rotation preventing mechanism for preventing the rotation of movable scroll 38 around eccentric bush 50 is provided between end plate 38 a of each movable scroll 38 and end wall 12 b or end plate 14. The rotation preventing mechanism includes, for example, a crank pin 54, and the crank pin 54 connects between end wall 12 b or end plate 14 and end plate 38 a via two ball bearings 56.

Where, counter weights 58 are attached to drive shaft 20 at positions of both sides of rotor 18, and the counter weights 58 become balance weights for the orbital movements of movable scrolls 38. High-pressure ports 60 and low-pressure ports (not shown) are provided on compression casing 30 for supplying and discharging high-pressure and low-pressure refrigerants to and from both scroll units 35. In more detail, each high-pressure port 60 provided through the end wall of compression casing 30, namely, the central part of end plate 36 a of fixed scroll 36, and pressure chamber 40 positioned at the central part of end plate 36 a is connected to high-pressure region 2 a of circulation passageway 2 via the high-pressure port 60. The low-pressure port is provided through the circumferential wall of compression casing 30, and the inside of compression casing 30 is connected to low-pressure region 2 b of circulation passageway 2 via the low-pressure port.

Hereinafter, the operation of scroll fluid machine 1 in the above-described refrigeration circuit will be explained.

When rotor 18, that is, drive shaft 20, is rotated by the power supply to stator 16, accompanied with the rotation of drive shaft 20, movable scroll 38 is served to an orbital movement via eccentric bush 50. By this orbital movement, scroll unit 35 on the left side in FIG. 1 carries out the following compression process.

First, the left-side scroll unit 35 sucks low-pressure gas refrigerant from low-pressure region 2 b of circulation passageway 2 into pressure chamber 40 positioned at the outer circumferential region through the low-pressure port and the space between scroll unit 35 and compression casing 30. Thereafter, the pressure chamber 40 having sucked the refrigerant moves toward the central portions of end plates 36 a, 38 a along scroll walls 36 b, 38 b, and during this movement, the refrigerant in the pressure chamber 40 is compressed by reduction of the volume of the pressure chamber 40. Then, the refrigerant compressed in the pressure chamber 40 flows out to high-pressure region 2 a of circulation passageway 2 through high-pressure port 60 when the pressure chamber 40 is communicated with the high-pressure port 60 at the central portions of end plates 36 a, 38 a.

The high-pressure gas refrigerant flowed into high-pressure region 2 a is cooled and condensed at condenser 4, and after becoming a high-pressure liquid refrigerant, bubbles and moisture are removed at receiver 6. The high-pressure liquid refrigerant having passed through receiver 6 is supplied to the right-side scroll unit in FIG. 1, and this right-side scroll unit 35 carries out the following expansion process.

In the right-side scroll unit 35, the high-pressure liquid refrigerant sent from high-pressure region 2 a of circulation passageway 2 flows into pressure chamber 40 positioned at the central portions of end plates 36 a, 38 a through high-pressure port 60. Thereafter, the pressure chamber 40, into which the refrigerant has flowed, moves toward the outer circumferential portions of end plates 36 a, 38 a along scroll walls 36 b, 38 b, and during this movement, the refrigerant in the pressure chamber 40 is expanded by increase of the volume of the pressure chamber 40.

The refrigerant expanded in pressure chamber 40 flows into low-pressure region 2 b of circulation passageway 2 through the space between scroll unit 35 and compression casing 30 and the low-pressure port at the outer circumferential region of scroll unit 35 when the pressure chamber 40 communicates with the space. The gas/liquid mixed low-pressure refrigerant flowed out to low-pressure region 2 b becomes low-pressure gas refrigerant, and thereafter, the refrigerant is sucked again into pressure chamber 40 of left side scroll unit 35.

In the above-described scroll fluid machine 1, a part of chip seal 42 (that is, a radial projection) is radially projected from the outer wall surface of scroll wall 36 b, 38 b, and fine gap G is secured between the inner and outer wall surfaces of scroll walls 36 b, 38 b, thereby relaxing the sliding contact conditions between scroll walls 36 b, 38 b. Consequently, the abrasion of scroll walls 36 b, 38 b can be suppressed in this scroll fluid machine 1.

Further, in this scroll fluid machine 1, because a part of chip seal 42 (radial projection) secures the fine gap G between the inner and outer wall surfaces of scroll walls 36 b, 38 b, even in a case where movable scroll 38 is in an orbital movement at a high speed, the orbital posture of the movable scroll 38 is not be disturbed. As a result, occurrence of galling between scroll walls 36 b, 38 b can be prevented.

Thus, since the abrasion of scroll walls 36 b, 38 b can be suppressed and the occurrence of galling between scroll walls 36 b, 38 b can be prevented by a part of chip seal 42 (radial projection), this scroll fluid machine 1 has an excellent durability. Besides, in this scroll fluid machine 1, because the fine gap G is secured between scroll walls 36 b, 38 b, even if lubricant oil is not mixed in the refrigerant, seizure does not occur between scroll walls 36 b, 38 b. Therefore, in a refrigeration circuit applied with this fluid machine 1, it is possible to make the refrigeration circuit oil-free, and in such a case, because a lubricant oil is not mixed in the refrigerant, the circuit has a good coefficient of performance. Moreover, because it is not necessary to mix a lubricant oil in the operational fluid, this fluid machine 1 can be applied to various uses.

Further, in this refrigeration circuit, since scroll units 35 each functioning as a compressor or an expander are provided to both ends of the drive shaft, it is possible to save the consumption power. This is because the expansion of the refrigerant in pressure chamber 40 of right-side scroll unit 35 gives an auxiliary power to drive shaft 20 via the orbital movement of movable scroll 38, and by utilizing this auxiliary power, the refrigerant can be compressed in pressure chamber 40 of left-side scroll unit 35.

Where, in this scroll fluid machine 1, it is possible to maintain the sealability of pressure chamber 40 by making the fine gap G several-tens μm or less.

The present invention is not limited to the above-described embodiment, and various modifications can be employed.

For example, although, in the above-described embodiment, pins 42 a are formed on chip seal 42 and pin holes 46 a are formed on flat surface 46 as a holding means for holding chip seal 42 on scroll walls 36 b, 38 b, the pin holes may be formed on chip seal 42 and the pins may be formed on flat surface 46. However, from the viewpoint of the productivity of the fluid machine, it is preferred that pins 42 a are formed on chip seal 42 and pin holes 46 a are formed on flat surface 46.

Further, as the holding means, a projected strip may be formed instead of pins 42 a, and as shown in FIG. 7, a groove 46 b for fitting the projected strip thereinto may be formed instead of pin holes 46 a. Namely, the holding means may be provided between scroll walls 36 b, 38 b and chip seal 42 and may include a recessed portion and a projected portion being engaged with each other, and by such a holding means, chip seal 42 can be held by scroll walls 36 b, 38 b easily and securely.

Moreover, the holding means may include an adhesive layer 70 as shown in FIG. 8, or the holding means may be formed only by adhesive layer 70. Further, although a part of chip seal 42 is projected from the outer wall surface of scroll wall 36 b or 38 b in the aforementioned embodiment, a part of chip seal 42 may be projected from the inner wall surface of scroll wall 36 b or 38 b.

Further, as shown in FIG. 8, a chip seal 72 having a portion projected from the outer and inner wall surfaces of scroll wall 36 b or 38 b may be employed. In this case, when pressure chamber 40 is formed, outer wall surface 72 c and inner wall surface 72 d of chip seal 72 is in sliding contact with the inner wall surface and outer wall surface of counter-side scroll wall 36 b or 38 b, and a fine gap G is secured at each sliding contact portion. Therefore, in this case, although chip seal 72 may be provided on both of fixed and movable scrolls 36, 38, chip seal 72 may be provided on one of fixed scroll 36 and movable scroll 38, and a conventional chip seal may be provided on the other scroll.

Further, as shown in FIG. 9, a radial projection 76 may be provided as a member separate from a conventional chip seal 74. In this case, by radial projection 76, a fine gap G can be secured between the inner and outer wall surfaces of scroll walls 36 b, 38 b. However, in a case where chip seal 74 and radial projection 76 are formed separately from each other, because the number of parts increases and it is necessary to provide means for holding chip seal 74 and radial projection 76 on scroll walls 36 b, 38 b, respectively, thereby causing a reduction of productivity and an increase of cost of the fluid machine, a structure is preferred wherein a part of chip seal 42 is projected from the outer wall surface as in the aforementioned embodiment. In other words, it is preferred that radial projection 76 is formed integrally with chip seal 74.

Further, if a part of chip seal 42 is projected from the outer wall surface of scroll wall 36 b or 38 b as in the aforementioned embodiment, because a fine gap G between scroll walls 36 b, 38 b is defined at a position most apart from the end of drive shaft 20 supporting movable scroll 38, even if the movable scroll 38 is operated at a high-speed orbital movement, the disturbance of the orbital posture of the movable scroll 38 can be prevented securely.

Furthermore, if a part of chip seal 42 is projected from the outer wall surface of scroll wall 36 b or 38 b as in the aforementioned embodiment, because a seal surface 42 b can be formed also on the projected portion, during the operation of the fluid machine, the surface pressure between chip seal 42 and end plates 36 a, 38 a can be reduced, and the durability of chip seal 42 can be increased. Therefore, as chip seal 42, it is preferred that seal surface 42 b extends up to the projected portion in the width direction and an outer side surface 42 c is connected perpendicularly to the side edge of the seal surface 42 b.

In fluid machine 1 according to the aforementioned embodiment, it is preferred that chip seal 42 is made of one material selected from the group consisting of a polyphenylenesulfide group resin (PPS group resin), a polyetheretherketone group resin (PEEK group resin) and a polyimide group resin (PI group resin), because these resins are excellent in abrasion resistance, thereby further improving the durability of the fluid machine.

Although fluid machine 1 according to the aforementioned embodiment has two scroll units 35 provided on both end portions of drive shaft 20, the scroll fluid machine according to the present invention may have at least one scroll unit.

INDUSTRIAL APPLICATIONS OF THE INVENTION

The scroll fluid machine according to the present invention can be applied to any fluid machine having a scroll unit, and in particular, it is suitable as a fluid machine used for a refrigeration circuit in an air conditioning system for vehicles. 

1. A scroll fluid machine having a scroll unit that comprises a fixed scroll and a movable scroll each constructed from an end plate and a scroll wall integral with said end plate, and comprises a chip seal provided at a tip of a scroll wall of one of said scrolls and in relative sliding contact with an end plate of the other scroll, characterized in that said scroll unit further comprises a radial projection provided on a first wall surface as one of wall surfaces of said scroll walls facing each other and being in relative sliding contact with a second wall surface as the other wall surface to secure a fine gap between said wall surfaces when a pressure chamber is formed between said fixed scroll and said movable scroll.
 2. The scroll fluid machine according to claim 1, wherein said radial projection is formed integrally with said chip seal.
 3. The scroll fluid machine according to claim 2, wherein said chip seal includes a top seal surface which is in relative sliding contact with said end plate of said the other scroll, and a sliding contact surface which is connected perpendicularly to a side edge of said top seal surface and which is positioned relatively to said first wall surface with a distance corresponding to said fine gap.
 4. The scroll fluid machine according to claim 2, wherein said scroll unit further comprises a holding means for holding said chip seal at said tip of said scroll wall.
 5. The scroll fluid machine according to claim 4, wherein said holding means comprises a recessed portion and a projected portion which are provided on said chip seal and said scroll wall and which are engaged with each other.
 6. The scroll fluid machine according to claim 4, wherein said holding means comprises an adhesive layer.
 7. The scroll fluid machine according to claim 1, wherein said chip seal is made of one material selected from the group consisting of a polyphenylenesulfide group resin, a polyetheretherketone group resin and a polyimide group resin.
 8. The scroll fluid machine according to claim 1, wherein a motor is further provided, and said scroll unit is provided on each end of a rotational shaft of said motor. 